[Freesurfer] contrast matrix

Hi Freesurfers,

My experimental design includes 3 discrete factors and 1 continuous variables:

Discrete factors: diagnosis with two levels (A, B); genotype with two levels (G, T); gender (F, M)

Continuous variable: age

So I can get 8 classes: AGF, AGM, ATF,ATM, BGF, BGM, BTF, BTM. Then I want to perform 2 (diagnosis)* 2(genotype) interaction analysis with regressing out the effect of gender and age. Is the following contrast matrix correct?

0.25 0.25 -0.25 -0.25 -0.25 -0.25 0.25 0.25 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0.25 0.25 -0.25 -0.25 -0.25 -0.25 0.25 0.25

Any help will be very appreciated.

Best wishes,

Meng